Qualitative analysis of oils



Patented Aug. 3, 1937 UNITED STATES PATENT OFFICE Robert E. Burk, Cleveland, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing.

Application October 9, 1934,

Serial No. 747,581

4 Claims.

This invention relates to qualitative and quantitative analysis, and more particularly analysis of mineral oils; and it is among the objects of the invention to provide a process and reagent for 5 the rapid determination of degradation products in mineral oils which have been in use under high temperatures as in engines. Other objects and advantages will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

I have found that lubricating oils lose their effectiveness in proportion particularly as degradation products develop, as from subjection to high engine temperatures in the presence of oxygen, and while the nature of these degradation products is obscure, they exhibit the properties of high molecular weight aggregates of nonlubricating character, and perhaps with some oxidation; and in accordance with the invention a reagent is employed such as to have a differential solvent action for the oil, but not for the degradation products.

The oil to be tested, as for example, a crankcase oil, is added in determined small amount to a larger amount of the reagent which is a differential solvent for the oil but not of the degradation 35 products therein. The mixture is stirred together thoroughly, and is then allowed to separate, the degradation products segregating out into a clear-cut visible layer. The analysis may be run with high precision where desired, or on 40 the other hand where this is unimportant, it may be operated as a quick qualitative test. The reagent may comprise alcohols or mixtures of alcohols, or less desirably alcohols and minor proportions of light hydrocarbons. Methyl, ethyl, 45 propyl, isopropyl, butyl, amyl alcohols for instance. An example of such compounding is about 80 per cent isopropanol and about 20 per cent butanol. Also combinations of ethyl and 50 butyl alcohols, or isopropyl and amyl alcohols.

In operating the analysis along precision lines, a calibrated tube on the order of a narrow graduated test tube or graduate may be employed, and an amount of the reagent, such as 9 cc. of the reagent comprising about 80 per cent isopropanol and about 20 per cent butanol is introduced into the tube, and then 1 cc. of the oil from the engine crank case is added, and the tube is well shaken, and then set aside, or centrifuged, to separate the degradation products as a visible layer, the height of which can be read oil on the graduation. If desired, the amount of the degradation products may be determined by weight, since a clean-cut separation from the reagent and dissolved oil is easily possible.

For a quick qualitative test 2 cc. of the reagent, alcohol or preferably the compounded alcohol mixture, such as about 80 per cent isopropanol and about 20 per cent butanol, is placed in a small test tube, and about 4 drops of the crank case oil is added. The tube is well shaken for a few seconds, and is then allowed to settle. Any degradation products present separate out as a visible layer at the bottom.

Other modes of applying the principle of the invention may be employed, change being made however, as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:- 7

1. A process of analyzing used mineral crankcase oils, which comprises adding a determined amount of the used mineral lubricating oil to a larger amount of a difierentialsolvent including about 80 per cent isopropanol and 20 per cent butanol, admixing thoroughly, and then allowing the mixture to separate out such degradation products as a visible layer.

2. As a new analytical reagent for analyzing mineral crankcase oils, a differential solvent discriminating between the oil and degradation products therein, such solvent being composed of about 80 per cent isopropanol and. 20 per cent butanol.

3. A process of analyzing used oils, which comprises Withdrawing used oil from an internal combustion engine, admixing isopropanol and butanol therewith to segregate any heat degradation products in such oil, and allowing the mixture to stratify.

4. A process of analyzing used oils, which comprises withdrawing used oil from an internal combustion engine, admixing an alcohol in predominant amount therewith to segregate any heat degradation products in such oil, and allowing the mixture to stratify.

ROBERT E. BURK. 

